If it is a shower tub surround they are usually glued to the wall and attached with plastic button. If you can pull it out you can reglue the plastic wall surround with a caulking they sell at home depot for this purpose. Same caulking that youuse to install them at home. This special caulking will not damage the plastic of your surround. You can install these specials holding buttons around the perimeter of your wall enclosure after. This is only a way to do it. The other way is to install a new tub surround.